Problem: A permutation p is an ordered group of numbers p1, p2, ..., pn, consisting of n distinct positive integers, each is no more than n. We'll define number n as the length of permutation p1, p2, ..., pn.

Simon has a positive integer n and a non-negative integer k, such that 2k ≤ n. Help him find permutation a of length 2n, such that it meets this equation: <image>.

Input

The first line contains two integers n and k (1 ≤ n ≤ 50000, 0 ≤ 2k ≤ n).

Output

Print 2n integers a1, a2, ..., a2n — the required permutation a. It is guaranteed that the solution exists. If there are multiple solutions, you can print any of them.

Examples

Input

1 0


Output

1 2

Input

2 1


Output

3 2 1 4


Input

4 0


Output

2 7 4 6 1 3 5 8

Note

Record |x| represents the absolute value of number x. 

In the first sample |1 - 2| - |1 - 2| = 0.

In the second sample |3 - 2| + |1 - 4| - |3 - 2 + 1 - 4| = 1 + 3 - 2 = 2.

In the third sample |2 - 7| + |4 - 6| + |1 - 3| + |5 - 8| - |2 - 7 + 4 - 6 + 1 - 3 + 5 - 8| = 12 - 12 = 0.

Solution (in JAVA):

Solution:
import java.util.*;
import java.io.*;
import java.math.BigDecimal;
import java.math.BigInteger;

import static java.lang.Math.*;
import static java.util.Arrays.*;
import static java.util.Collections.*;



 
 
public class Main {
	public static void main(String[] args) throws Exception{
		InputReader in = new InputReader(System.in);
		PrintWriter out = new PrintWriter(System.out);
		TaskA solver = new TaskA();
		solver.solve(1, in, out);
		out.close();
	}

static class TaskA {
	
	
  // GCD && LCM 
	 long gcd(long a ,long b){return b == 0 ? a : gcd(b , a % b);}
	 long lcm(long a , long b){return a*(b/gcd(a, b));}
 // REverse a String 
	String rev(String s){
		return new StringBuilder(s).reverse().toString();
	}
	
	
	/*          SOLUTION  IS RIGHT HERE     */
	
	
	public void solve(int testNumber, InputReader in, PrintWriter out){
		 // n br = new BufferedReader(new InputStreamReader(System.in));
		 // Scanner sc = new Scanner(System.in);
		int n = in.nextInt() , 
				k = in.nextInt();
		
		for(int i = 0; i < n; i++){
			if(i < k)
				out.print( (2*i + 1) + " " + (2*i + 2 ) + " ");
			else
				out.print((2*i + 2) + " " + ( 2 * i + 1) + " ");
		}
	}
}  

 // ||||||| INPUT READER ||||||||
 static class InputReader {
	private byte[] buf = new byte[8000];
	private int index;
	private int total;
	private InputStream in;
	BufferedReader br = new  BufferedReader(new InputStreamReader(System.in));
	public InputReader(InputStream stream){
		in = stream;
	}
	
	public int scan(){
		if(total == -1)
			throw new InputMismatchException();
		if(index >= total){
			index = 0; 
			try{
			total = in.read(buf);
			}catch(IOException e){
			   throw new InputMismatchException();
			}
			if(total <= 0)
				return -1;
		}
		return buf[index++];
	}
	public long scanlong(){
		long integer = 0;
		int n = scan();
		while(isWhiteSpace(n))
			n = scan();
		int neg = 1;
		if(n == '-'){
			neg = -1;
			n = scan();
		}
		while(!isWhiteSpace(n)){
			if(n >= '0' && n <= '9'){
				integer *= 10;
				integer += n - '0';
				n = scan();
			}
			else throw new InputMismatchException();
		}
		return neg*integer;
	}
	
	private int scanInt() {
		int integer = 0;
		int n = scan();
		while(isWhiteSpace(n))
			n = scan();
		int neg = 1;
		if(n == '-'){
			neg = -1;
			n = scan();
		}
		while(!isWhiteSpace(n)){
			if(n >= '0' && n <= '9'){
				integer *= 10;
				integer += n - '0';
				n = scan();
			}
			else throw new InputMismatchException();
		}
		return neg*integer;
	}
	
	public double scandouble(){
		double doubll = 0;
		int n = scan();
		int neg = 1;
		while(isWhiteSpace(n))
			n = scan();
		if(n == '-'){
			neg = -1;
			n = scan();
		}
		while(!isWhiteSpace(n) && n != '.'){
			if(n >= '0' && n <= '9'){
				doubll *= 10;
				doubll += n - '0';
				n = scan();
			}
		}
		if(n == '.'){
			n = scan();
			double temp = 1;
			while(!isWhiteSpace(n)){
				if(n >= '0' && n <= '9'){
					temp /= 10;
					doubll += (n - '0')*temp;
					n = scan();
				}
			}
		}
		return neg*doubll;
	}
	
	private float scanfloat() {
		float doubll = 0;
		int n = scan();
		int neg = 1;
		while(isWhiteSpace(n))
			n = scan();
		if(n == '-'){
			neg = -1;
			n = scan();
		}
		while(!isWhiteSpace(n) && n != '.'){
			if(n >= '0' && n <= '9'){
				doubll *= 10;
				doubll += n - '0';
				n = scan();
			}
		}
		if(n == '.'){
			n = scan();
			double temp = 1;
			while(!isWhiteSpace(n)){
				if(n >= '0' && n <= '9'){
					temp /= 10;
					doubll += (n - '0')*temp;
					n = scan();
				}
			}
		}
		return neg*doubll;
	}
	public String scanstring(){
		StringBuilder sb = new StringBuilder();
		int n = scan();
		while(isWhiteSpace(n))
			n = scan();
		while(!isWhiteSpace(n)){
			sb.append((char)n);
			n = scan();
		}
		return sb.toString();
	}
	
	
	public boolean isWhiteSpace(int n){
		if(n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1)
			return true;
		return false;
	}
/// Input module 	
	
	public int nextInt(){
	  return scanInt();
	}
	
	public long nextLong(){
		  return  scanlong();
		}
	
	public double nextDouble(){
		  return  scandouble();
		}
	
	public float nextFloat(){
		  return scanfloat();
		}

	public String next(){
		return scanstring();
	}
	
	public String nextLine(){
		String S = "";
		try {
			S = br.readLine();
			 br.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return S;
	}
	
	public int[] readIntArray(int size)  {
        int[] array = new int[size];
        for (int i = 0; i < size; i++) {
            array[i] = nextInt();
        }
        return array;
    }
}
 
}